Does using iCloud save memory on the iPhone?

I have a lot of pictures and I take a lot of pictures, so I would like to know if using iCloud would help my memory and storage capacity of my phone.

I'm not 100% sure of how iCloud even works. Does it only take up app space on your phone and then you can access any photo on the iCloud database without it taking up space? Or does using iCloud take up even more space as it would take up space and so would the photos I choose to go into it.

Yes it backs up contacts and photos

ICloud is storage separate from your phone, it is not an app.therefore it doesn't take up any space on your phone. However is limited to 5gb so beyond requires additional iCloud space purchase

And with iCloud, I don't believe you can specifically choose what photo you want specifically to store.

Think of it as a bank where you know that you have money in it, but you can't see the money
There are other apps such as dropbox (3rd Party app) which have a more user friendly and accessible setup in comparison to iCloud and you can access anything you put into dropbox anywhere from your iPhone or any device that has dropbox ie) computer and tablets

Or you could go into your phone directly and take out which photos you wanted to save and put them into a folder or something on your computer

Assuming you're using windows, you go to My Computer and go to portable devices
Select that device and continue to open folders until you discover your photos
create a folder on your computer to store them in
then just drag and drop the photos you'd like to save

This can also be achieved in your itunes.however, you may not choose which photos you want to save from your phone onto your computer so it'll carry all of them onto it.

Also please be reminded that my answers are just suggestions and basic/amateur knowledge